The immediate goal of this pilot project is to develop tools for the engineering analysis and design of composite restorations. The ultimate goal is to improve placement techniques and cavity designs in order to increase restoration longevity while conserving healthy tooth structure and minimizing iatrogenic complications. The focus is on clinical problems (open margins, tooth sensitivity, recurrent decay, discoloration, etc.) associated with stresses developed during the polymerization shrinkage of composite resins. The approach in this study is to analyze placement techniques and cavity designs with the application of a state-of-the-art stress calculation tool (Finite Element Method, FEM). The FEM will be used to calculate the stresses developed during the placement of self- and light-cured Class V composite restorations. The specific aims include the following. FEM methods must be developed to model the polymerization process and the associated shrinkage. The algorithm will take into account the crucially dissimilar behaviors of self- vs. light-cure materials. Those models will then be used to compare the stresses that are developed with different placement techniques into different cavity designs. Then, placement methods and cavity preparation design changes will be investigated for minimization of stress build-up. Finally, based on the numerically developed information, laboratory tests will be performed to validate the FE model.